The scale and performance of large distributed computing systems may be limited by power constraints, both at the site and system level. Future systems may run under a power bound to ensure that the site and system stays within power limits, wherein the limits may derive from constraints on operational costs or limitations of the cooling and power delivery infrastructure. Bounds on system power may be enforced by actively controlling the power consumption of each concurrent job running in the system. Conventional technologies for bounding job power may be designed for systems that rarely approach power bounds. As such, conventional technologies may rely on conservative guard bands that waste power and use inefficient mechanisms for reducing power that substantially degrade job performance. Indeed, communications network power is one component of job power for which current approaches tend to employ overly conservative guard bands on a continual basis.